Mount St. Helens. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome.ount St. Helens. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome.
Definition of plantar. : of or relating to the sole of the foot plantar wart.
The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument.The reflex can take one of two forms. In normal adults the plantar reflex causes a downward response of the hallux (flexion).An upward response (extension) of the hallux is known as the Koch sign, or as the Babinski response or Babinski sign, named after the neurologist Joseph Babinski.he plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument.